Star Wars Rebels greatest intelligence asset is finally uncovered by the Empire. Through Imperial Eyes is told from the point of view of Agent Kallus (David Oyelowo). He is the Imperial security officer who has been leaking information to the rebels under the code name "Fulcrum". The Fulcrum storyline has been one of the most intriguing plot threads this season. Kallus has kept the rebels one step ahead of the tightening noose. But the jig is up, Grand Admiral Thrawn's (Lars Mikkelsen) keen intellect finally reveals the mole.

Through Imperial Eyes opens with Kallus being awakened by a stormtrooper. He races to the bridge. A stolen shuttle is trying to escape the Empire's blockade of Lothal. The earnest Lt. Lyste (Liam O'Brien) orders a TIE fighter attack. The shuttle is hit, then pulled into the cruiser by a tractor beam. Kallus takes his men to investigate. He's stunned to find that the shuttle's masked pilot is none other than Ezra Bridger (Taylor Gray). He's taken to the detention center for interrogation. Also in the shuttle are AP-5 (Stephen Stanton) and Chopper. AP-5 claims they were kidnapped when the shuttle was stolen.

Kallus tells Lyste that he will question the prisoner alone. Inside the cell, Kallus berates Ezra for this stunt. He's even more surprised to learn that Ezra has come to rescue him. Fulcrum's transmissions have been monitored by the Empire. The rebels believe Kallus is about to discovered and executed. As the cell door opens, Ezra throws himself into Kallus' fist, begging for mercy. Lyste and his men walk in, impressed by Kallus' tactics.

Lyste informs them that Grand Admiral Thrawn has arrived. He wants to meet the prisoner. Lyste and Kallus take Ezra to the Chimaera, Thrawn's Star Destroyer. AP-5 and Chopper slickly join the party. Lyste remembers his failure with "the princess from Alderaan". He hopes this capture will prove his worth.

Ezra is brought to the detention center on the Chimaera. Meanwhile, Chopper has sent a signal from a communication port to their back-up. Rex (Dee Bradley Baker) and Kanan (Freddie Prinze Jr.), in stormtrooper armor, are on a stolen Imperial ship heading to Lothal. Their plan was to extract Kallus from the cruiser. They don't have the command codes to infiltrate the Chimaera. Chopper and AP-5 must find a way to get those codes.

Kallus and Lyste reach Thrawn's office. They must provide their security codes to enter. They walk in to find Thrawn battling two ferocious security droids. They are impressed by his tremendous fighting skills. Thrawn has the brawn to match his brain. Thrawn invites them in, along with Admiral Constantine (Dee Bradley Baker), and Col. Wullf Yularen (Tom Kane), another character from The Clone Wars.

Thrawn tells the assembled men that Fulcrum must be found. He deduces that the traitor must be a high-ranking officer of the inner circle. Col. Yularen is there to question each of them. Thrawn activates his holo-projector. He also tells them that he is very close to finding the rebels secret base. Kallus is clearly alarmed at this news. As they leave Thrawn's office, Kallus and Lyste bump into Governor Pryce (Mary Elizabeth McGlynn). Kallus whispers to Lyste that she is most likely the spy. That he must watch her every move. Lyste is energized by this secret duty. As he walks away, Kallus steals his code cylinder.

Pryce tells Thrawn that the traitor is one the ship. They monitored Chopper's transmission to Rex and Kanan. Thrawn decides it's time to meet the prisoner. At the cell, Kallus uses Lyste's security code to deactivate the cell. Kallus demands Ezra tell him the location of the rebel base. Ezra refuses, he doesn't trust Kallus with that information. AP-5 has an idea. If they can get into Thrawn's office, they can erase the data from his map and get the command codes for the ship.

Thrawn and Pryce arrive to find the cell empty, except for the shuttle pilot's helmet. They are even more unnerved to find that Lyste's codes had been used to free the prisoner. Meanwhile, Ezra has changed into an officer's uniform to impersonate Lyste. They go to Thrawn's office. Ezra uses the Jedi mind trick. The stormtrooper opens the door. Once inside, Ezra wants to take the stolen Syndulla family totem back, but Kallus says they have no time for such things. Chopper retrieves the command codes, sends them to Kanan, and erases Atollon from Thrawn's map. They are about to leave when AP-5 warns them that Thrawn is about to enter the room.

Kallus tells Ezra and Chopper to hide. As Thrawn walks in, he is attacked by his security droids, who were quickly turned on by Kallus. Thrawn fights the droids while Ezra, Chopper, and Kallus escape. Above Lothal, Rex and Kanan drop out of hyperspace smack dab into the Imperial blockade. The codes work. They land in the Chimaera's hangar, but are met by Governor Pryce. She demands they remove their helmets. Kanan tries the mind trick, but it doesn't work on her. She stuns Kanan then gets into a fight with Rex.

Lyste sees Pryce fighting a trooper and stuns her, thinking she is the traitor. Ezra thanks him as the team grabs Kanan and boards the ship. Kallus knocks out Lyste from behind. He switches back the code cylinder. He then refuses to leave. He can do more if he stays behind as Fulcrum. The shuttle takes off and the rebels escape as Thrawn enters the bay. Lyste is awoken and branded the traitor by Kallus. He is dragged away shocked by the accusation.

In Thrawn's office, Pryce commends Kallus for saving her and trying to stop the shuttle. Thrawn agrees. When Pryce and Kallus leave, Col. Yularen says the whole operation seems staged. Thrawn points to the helmet recovered from the shuttle pilot. It had a drawing of a Lothal cat. Thrawn shows the various items he's recovered from Phoenix squadron. Almost everything has Sabine's (Tya Sircar) artwork, especially her fondness for the Lothal cat. Thrawn deduces the pilot had to be Ezra Bridger. Yularen is stunned, why didn't Kallus inform them? Thrawn calmly replies that Kallus is Fulcrum.

Kallus' outing as Fulcrum puts the rebels square in Thrawn's sights. He can feed Kallus bogus information to set up the rebels. Even worse is Kallus' belief that he has earned more respect from Thrawn after the set-up of Lyste. The rebels are now at their most vulnerable. Next week's episode hints at the return of Maul, drum roll please, and the introduction of Obi Wan Kenobi to Star Wars Rebels. The endgame is heating up considerable on Disney XD.